On Mon, 15 Jun 2015 13:32:01 -0400 (EDT) Vince Weaver <vincent.wea...@maine.edu> wrote:
> On Thu, 26 Mar 2015, Jacob Pan wrote: > > > RAPL energy hardware unit can vary within a single CPU package, e.g. > > HSW server DRAM has a fixed energy unit of 15.3 uJ (2^-16) whereas > > the unit on other domains can be enumerated from power unit MSR. > > There might be other variations in the future, this patch adds > > per cpu model quirk to allow special handling of certain cpus. > > So I have a Desktop Haswell machine (model 60) that is instrumented > to measure actual DRAM power at the DIMM (with a sense resistor). > > We are consistently getting RAPL results roughly a factor of 2 > smaller than the actual, measured results. > > Does desktop Haswell have a similar units issue to Haswell-EP? > Not that I know of. perhaps has to do with the difference of what and where we are measuring. Let me find a instrumented system to verify and get back to you. > I wasted a bunch of time trying to decode the > DRAM_ENERGY_SCALEFACTOR_MCHBAR values described in the > Desktop 4th Generation Intel Core Processor Family > datasheet but possibly that value in the MCHBAR is unrelated to the > one exported by the RAPL interface. > This scale factor is not directly related to the energy counter. The MMIO DRAM RAPL energy status uses the same unit as the MSR interface, the resolution is ~61uJ. > Vince [Jacob Pan] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
